its a type of matting used for animals, thick fibers woven into a base that provide comfort and also allows water to wick away from the top part.
I have vet bed in the back of my car, my dog dribbles and is elderly so the dribble goes under the vetbed and is absorbed by the towel underneath, the vet bed provides a softer cushion on her old joints more so than just a liner in the boot.
I also have vet bed in the pen, its up the top level with towel and newspaper underneath to absorb the wee, my lot love to sleep ontop the vet bed.